JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://code.jquery.com/qunit/qunit-1.12.0.js"></script>
<link rel="stylesheet" href="http://code.jquery.com/qunit/qunit-1.12.0.css">
<div id="qunit"></div>
<div id="qunit-fixture"></div>

JavaScript

function VM() {
    var self = this;

    this.Status = ko.observable(false);

    this.A = ko.observable();

    this.B = ko.computed(

    function () {
        return self.A();
    }).extend({
        throttle: 200
    });

    this.B.subscribe(

    function () {
        self.Status(true);

        setTimeout( //ajax simulation
        function () {
            self.Status(false);
        }

        , 200)
    });

}

test("hello test", function () {
    var sut = new VM();
    sut.Status(true);
    equal(sut.Status(), true);
});

asyncTest("computed with ajax", function () {
    expect(2); // expenting two asserts
    var sut = new VM();
    sut.A('something');
    sut.A('something2');
    sut.A('something3');
    stop();
    var callCount = 0;
    var expectedValues = [true, false];
    sut.Status.subscribe(function (value) {
        start();
        equal(sut.Status(), expectedValues[callCount]);
        callCount++;
    });
});